Strange pain on my left side—anyone else experienced this?

For the past few days, I’ve been experiencing this rather peculiar sensation on my left side, situated just beneath the ribs and drifting somewhat toward my lower back, roughly where it's indicated in this image, perhaps even a bit closer to the kidney area:
http://i43.tinypic.com/bfriww.jpg

The pain itself isn't overwhelming in intensity, yet it carries a sharp quality, though it remains completely absent while I am simply resting or staying still. It only seems to manifest when I perform certain actions, such as taking a sudden, deep breath, coughing, or perhaps shifting into an awkward physical position:
Aside from these specific moments, I feel perfectly fine—being only 19 years old—but the unpredictability of it all is honestly quite aggravating. What are your thoughts on this?

I have a feeling that the pain isn't quite as sharp today, though I suppose I can't say for certain without further observation. Has anyone else noticed a similar shift?

Pancreas pain hits you right on that side, radiating from the front straight through to your back—it’s got this really distinct feel to it, but you're way too young for that kind of trouble... http://www.pancreaspain.org/